If you already have your S3 bucket recognized by Terraform and it was created by the code you pasted, you schould not be having any diffculties if the operation could be done in place.
There are a few important MUST KNOW things about how TF handle resources. MUST KNOW because in the end of the day it's infrastructure :) Some of the parameters are immutable, although it might not seem that intuitive changing the resource identifier would trigger delete/create scenario.
Could you paste your TF plan output ?
